1. Field of the Invention
The present invention relates to a flat panel display (FPD), and more particularly, to a flat panel display with a sealing channel filled with the sealing frit.
2. Description of the Prior Art
With the progressive development of the electronics industry, the demand for flat panel displays (FPD) has increased. The plasma display panel (PDP) has the greatest market potential amongst all FPDs. In the manufacturing process of a PDP, a front substrate is placed above a rear substrate, then these substrates are sealed together to form the discharge cell. The quality of the sealing process affects the yields of the subsequent processes for removing air and injecting the discharge gases from the PDP, and also influences the isolation of the discharge cells. Therefore, it is necessary to improve the reliability and quality of the sealing process.
Please refer to FIG. 1 and FIG. 2 which are the schematic diagrams of a plasma display panel 10 according to the prior art. The plasma display panel 10 includes a front substrate 12, and a rear substrate 14 parallel to and spaced apart from the front substrate 12 for forming a gap between the front substrate 12 and the rear substrate 14. A plurality of scanning electrodes 16, a dielectric layer 17, and a MgO layer 18 are formed on the front substrate 12. A display area 20 is defined on a surface of the rear substrate 14 that faces the front surface. Further, a plurality of barrier ribs 22 are positioned on the display area 20.
As shown in FIG. 1, in the sealing process of the front substrate 12 and the rear substrate 14, a sealing frit 24 is formed along the boundary of the display area 20 on the rear substrate 14. Then, a heating process is performed to sinter the sealing frit 24 so as to temporarily stabilize the sealing frit 24. As shown in FIG. 2, in the prior sealing method, a clamp 26 is used to hold the front substrate 12 and the rear substrate 14 tightly together in order to fix the distance between the front substrate 12 and the rear substrate 14. Furthermore, the front substrate 12 and the rear substrate 14 are placed into an oven of a temperature of approximately 450xc2x0 C. In the process, the sealing frit 24 made of low melting point glass, melts to bond the front substrate 12 together with the rear substrate 14. After cooling, the front substrate 12 and the rear substrate 14 are tightly fixed and sealed together.
The sealing frit 24 is formed along the boundary of the display area. Prior to sintering, the sealing frit 24 is soft and disperses easily but lacks uniformity in height. Due to the uneven height of the sealing frit 24, a space exists between part of the sealing frit 24 and the front substrate 12, and the front substrate 12 can""t be hermetically sealed with the rear substrate 14. The bonding strength between he two substrates becomes seriously affected and may cause gas leakage. As well, there is difficulty in the control of the coating path and the dispersion of the sealing frit powder. Moreover, positioning of the sealing frit 24 requires precise control, otherwise, the sealing frit 24 will pollute the display area 20 or other components. The clamp 26 requires the support of the barrier ribs 22 in the display area 20 for exerting some force in sealing the front substrate 12 with the rear substrate 14. However, the clamp 26 may rupture the MgO layer 18 in the display area 20 to influence the picture quality of the plasma display panel (PDP).
It is therefore an object of the present invention to provide a plasma display panel (PDP) having a sealing channel to solve the above-mentioned problems.
According to the present invention, the PDP includes a front substrate, a rear substrate parallel to and spaced apart from the front substrate for forming a gap between the front and rear substrates. A display area is positioned on the surface of the rear substrate that faces the front substrate. The plasma display panel further includes a plurality of barrier ribs positioned on the display area of the rear substrate, a first channel rib positioned on at least two sides of the display area of the rear substrate, and a second channel rib spaced from the first channel rib by a predetermined distance. The first channel rib and the second channel rib form a sealing channel. A sealing frit fills the sealing channel so as to seal the front substrate and the rear substrate together. Additionally, a joint notch can be formed on the front substrate. The position of the joint notch is opposite to the first channel rib and the second channel rib, so that top surfaces of the first and the second channel ribs are in contact with the surface of the joint notch. A plurality of grooves may additionally be formed on the top surface of the first or second channel ribs for increasing the effective sealing area of the sealing frit.
The sealing frit is formed in the sealing channel to eliminate the heating process used to temporarily sinter the sealing frit. The result prevents the destruction of the sealing frit during the sealing process and the sealing channel improves the uniformity of height as well as precisely controlling the position of the sealing frit. Hence, the yield and quality of the sealing process can be increased.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skills in the art after reading the following detailed description of the preferred embodiment, which is illustrated in the various figures and drawings.